Research On Deformation Mechanism Of Some Square Unstable Slope In Wanzhou District Of Chongqing

The unstable slope is located in the fengjiayuan region Peace Plaza Wanzhou District Chongqing city, it's longitudinal length is about 200m, front width of 96m, back width of 100m, flat area of 21000m2. The average thickness of the unstable slope is about 20m in the middlefront,and 8m in the middleback,volume of 2.8×105m3. the active slide direction is 43°in the middle-front and 60°in the back .with steep back and smooth front .the north boundary is in JiGongLing,and the south boundary is located in HeJiaGou. The deformation characteristics of the unstable slope is obvious, it appears many cracks and housing deformation in the back.It is particularly critical to know the formation mechanism and failure modes of the landslides, and correct evaluation of its stability.In this paper, the unstable slope of some square is taken as the research object. On the basis of previous studies, combined with field investigation, the geological environment of this study area is summarized.By analysising the measured monitoring data, the displacement characteristics of the monitoring point is studied. FLAC3D numerical simulation is adopted to analyze the original slope stability conditions and the stability and the stress characteristics of deformation field after the excavation on the basis of displacement characteristics, Details are as follows:(1) Based on the geological exploration data,find out the unstable slope area environment geology background ,volume of the unstable slope , rock structure, geo- logical structure, Characteristics of Groundwater , the characteristics of deformation and damage and so on.(2) FLAC 3D model is established based on the basic features of unstable slope. The numerical numbers of FLAC 3D and the experimental dates of some Square after the excavation of unstable slope are compared. If the result is matched, the model and parameter are reasonable.(3) The unstable slope under various working conditions is stable by the limit equilibrium method, in the based of the analysis of original conditions and the dates after the excavation of unstable slope of some Square. This is match with the actual situation.(4)Using FLAC3D numerical simulation to analyse field characteristics of stress and deformation in the conditions of natural and rainfall of unstable slopes in the original conditions and after excavation,find that:①In the original conditions, the back edge of unstable slopes has occurred creep deformation locally, but the shear strain increment is not completely through, unstable slopes as a whole is still in steady state.②After excavation,analyse under stress field and find that the minimum principal stress in leading edge and trailing edge of the unstable slopes showed obvious features of tensile stress; analyse under deformation field and find that the shear strain increment of unstable slopes is not completely through, unstable slopes as a whole is also in steady state,which is also consistent with field conditions and the stability analysis results in limit equilibrium.③Take monitoring points before, during and after the unstable slopes'surface, according simulating numerically Its displacement curve and analysing comparatively the deformation of unstable slopes,and further understand the deformation mechanism of unstable slopes.